1. Field of the Invention
The invention is a mobile hospital bed scale which slides under a hospital or nursing bed, with patient in situ. With a minimum of disturbance of the patient, a person can operate the mobile hospital bed scale to lift the entire bed slightly, with patient in place, as opposed to lifting the patient apart from the bed, and as opposed to implanting the scale in the bed; The mobile hospital bed scale is used to determine the weight of bed and patient. If a memory device is programmed with the tare weight of the bed, the patient""s weight can be determined, or stored for future recall and reference. The data can be downloaded to a computer for automated use and analysis. The mobile hospital bed scale is portable and can be moved from bed to bed. The bed can be operated by an electrically powered drive or can be battery operated.
2. Description of Related Art
Weighing bedridden hospital patients is a time consuming and unpleasant task. An obvious and unpleasant way to weigh patients is to put a sling underneath them, and hoist them by a spring scale. This disturbs the patient. Fosteret al, U.S. Pat. No. 5,672,849 is a variation on this theme and contemplates building the bed with a patient support built on a frame that can be raised and lowered on the bed. This requires the adaptation of all hospital beds to this scale, which is expensive. The present invention avoids that bed-by-bed expense and the disturbance of the patient.
In Stultz et al, U.S. Pat. No. 4,006,789, the inventor proposes to slide a horizontal table under the patient and then weigh the patient. The necessary tipping or related movement of the patient to get the scale underneath the patient is sometimes referred to as xe2x80x9clog-rolling.xe2x80x9d Not only does the invention disturb the patient, but the invention is somewhat bulky and takes up more storage space than the present invention. Swersey et al, U.S. Pat. No. 4,487,276, Dec. 11, 1984 attempts to eliminate some of the bulk by having a tip-up platform, but still requires sliding a horizontal table under the patient to weigh the patient. Hay et al, U.S. Pat. No. 5,319,817 Jun. 14, 1994 also contemplates a tip-up, fold-up horizontal platform slid under the patient. Both the sling and the horizontal table inventions require substantial movement of the patient. Such movement is one of the largest sources of disability injury to employees of ambulatory care facilities. Other patents such as Eisen, U.S. Pat. No. 5,612,515, Mar. 18, 1997, are of the same genre.
Swersey, U.S. Pat. No. 4,793,428, Dec. 27, 1988, is entitled xe2x80x9cHospital Bed with an Integrated Scale.xe2x80x9d As the name suggests the scale is in the bed. Weighing patients is very important and needs to be done for bedridden patients approximately once per day. The expense of equipping an entire ambulatory facility with such beds and bed scales is substantial. That expense for multiple beds is eliminated by the present invention.
Stith et al, U.S. Pat. No. 4,589,989, Apr. 29, 1986 contemplates a scale mounted on and in a bed frame. The invention appears intended for acute care. Koerber, Sr., U.S. Pat. 4,961,470 Oct. 9, 1990 also contemplates a weighing mechanism as part of the bed. The Stith and Koerber inventions are not practical for large multiple bed facilities because, again, weighing patients is very important and needs to be done for bedridden patients approximately once per day. The expense of equipping an entire ambulatory facility with such beds and bed scales is substantial. That expense for multiple beds is eliminated by the present invention. Other patents such as Bumbalough, U.S. Pat. No. 5,393,938 are of the same genre.
Carruth et al, U.S. Pat. No. 4,974,692, Dec. 4, 1990 contemplated a weigh bed with two frames, but contemplates that there will be a weigh frame associated with each bed. The frame is not adapted to be used with multiple types of beds. Carruth et al, U.S. Pat. No. 5,173,977, Dec. 29, 1992 also contemplated using a load cell, but not in a combination as facile or designed like the present invention.
Hasty et al, U.S. Pat. No. 5,393,935 takes a different approach by having multiple slats slid under a mattress with load cells on each end. It still requires patient movement and does not appear to contemplate a memory device for the tare weight of the mattress or for the patient weight.
The Engelsher art, U.S. Pat. No. 3,217,818, Nov. 16, 1965, uses a similar but different concept than the Hasty ""935 patent. Engelsher contemplates minimizing patient movement by placing a platform on a bed frame and using inflatable airtight means to communicate with a measuring device and determine weight from the pressure generated when the airtight means is pumped to hold the patient""s weight.
Waters et al, U.S. Pat. No. 4,669,136 falls in the same genre as the Stith invention as an in-bed weighing device.
Swersey et al, U.S. Pat. No. 4,281,730, has an xe2x80x9cunder bedxe2x80x9d scale which achieves many of the patient care objects of this invention and relieves a source of disability injury. However, that bed scale requires a pair of scales onto which the bed is rolled.
Whitecar, U.S. Pat. No. 3,341,992, Mar. 11, 1969 designed for use with a forklift, contemplates locating a series of cylinders under a platform and having pistons protrude through the platform to hold the lifted weight and then measure the weight by the resulting pressure on pre-pressurized cylinder pistons.
Zefira U.S. Pat. No. 5,739,478, Apr. 14, 1998, similar to Whitecar, designed for weighing pallets, contemplates cylinders below a platform and a retractable contact member that contacts the pallet.
Harvill, U.S. Pat. No. 4,002,115, somewhat similarly to Whitecar contemplates removing a display means and weighing a bulk storage tank, or alternatively, situating three jacks to lift a bulk storage tank.
Neuman, U.S. Pat. No. 5,747,745, May 5, 1998, provides for a housing for attachment to a lower portion of a bed and requires attachment to a bed. Neuman""s invention then requires that a support means must be extended. Once mounted to a bed in the housing, a load cell is used for weighing. The contemplation in the Neuman invention is to retrofit beds to have the Neuman system mounted on the beds.
Hillesheim, U.S. Pat. No. 4,403,680, Sep. 13, 1983, contemplates using a hydraulic cylinder to drive a scissors jack under a platform, and then measuring the resultintg pressure in the hydraulic driving cylinder to determine the weight of the object on the platform. A system of compensating for friction effects of the piston and the scissors system is included in the claims.
The present invention eliminates any patient movement with respect to the bed. The present invention only requires a small vertical movement of the bed on the platform sufficient to allow the platform to bear the weight of the patient and bed, which can be two inches of vertical lift of the bed or less.
Previous to the initial application for the underlying applications to this particular invention, the inventors had developed an initial model of the invention to review its potential attributes and experiment with it. That model was very simply a motorcycle lift with a platform with load cells placed on it. The motorcycle lift had a pivot mechanism with some horizontal displacement as the platform was raised. That model had to be dragged into position. The model required a user to stoop and therefore was not economically efficient for use. The model of the invention took too much personnel time to raise the bed. The model required a reset of tare weight for each weighing. Use of the model was abandoned. Thereafter, the invention referenced in U.S. application Ser. No. 09/097,128 was designed. This invention has been improved to provide for steady, even lifting by an electric power source, preferably using a screw drive, which may either be plugged in or be operated from a portable battery, and also has features which enable a more automated use of the invention.